A quantum resource theory is defined by a set of free operationsFor our purposes, quantum operations are completely positive and trace-preserving maps from linear operators on an input to linear operators on an output Hilbert space. and a set of free states with the property that free operations are closed under composition and map free states into free states [1]}, [2]}. Resource theories offer a general framework to quantify the usefulness of different quantum states and their interconvertibility using free operations.
Prominent examples of resource theories include entanglement theory (where local operations and classical communication are free and entanglement is considered a resource) [3]}, [4]}, [5]}, athermality in thermodynamics (where transformations that preserve the thermal state are free and states out of thermal equilibrium are resourceful) [6]}, [7]}, [8]}, and coherence (where incoherent states are free and coherence is considered a resource)  [9]}, [10]}, [11]}.
